Personal letters, also known as friendly letters, and social notes normally have five parts.
1. The Heading. This includes the address, line by line, with the last line being the date. Skip a line after the heading. The heading is indented to the middle of the page. If using preaddressed stationery, add just the date.
2. The Greeting. The greeting always ends with a comma. The greeting may be formal, beginning with the word "dear" and using the person's given name or relationship, or it may be informal if appropriate.
Formal: Dear Uncle Jim, Dear Mr. Wilkins,
Informal: Hi Joe, Greetings,
(Occasionally very personal greetings may end with an exclamation point for emphasis.)
3. The body. Also known as the main text. This includes the message you want to write. Normally in a friendly letter, the beginning of paragraphs is indented. If not indented, be sure to skip a space between paragraphs. Skip a line after the greeting and before the close.
4. The complimentary close. This short expression is always a few words on a single line. It ends in a comma. It should be indented to the same column as the heading. Skip one to three spaces (two is usual) for the signature line.
5. The signature line. Type or print your name. The handwritten signature goes above this line and below the close. The signature line and the handwritten signature are indented to the same column as the close. The signature should be written in blue or black ink. If the letter is quite informal, you may omit the signature line as long as you sign the letter.
Postscript. If your letter contains a postscript, begin it with P.S. and end it with your initials. Skip a line after the signature line to begin the postscript.
See also Layout of a friendly letter.
See also Commas in Letters and Capitalization in Letters